Disc Brake, In Particular for a Utility Vehicle

ABSTRACT

A disc brake for a utility vehicle, having a brake caliper which encompasses a brake disc and which is fastened, so as to be axially movable in relation to the brake disc, to a positionally fixed brake carrier by means of two fastening elements, wherein the fastening elements have in each case one guide bar which is fixedly connected to the brake carrier, of which guide bars, for the axial mobility of the brake caliper, one in guided in a plain bearing which is designed as a fixed bearing and the other is guided in a plain bearing which is designed as a floating bearing, wherein at least the floating bearing has a guide sleeve, which engages around the guide bar and which is connected to the brake caliper so as to be fixed in terms of movement, with an elastomer bearing sleeve, and the guide bar is covered, on its end side facing away from the brake disc, by means of a cap, is designed such that the cap, while covering the guide sleeve at the end side, is fastened at least in one axial partial region to the elastomer bearing sleeve.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT International Application No.PCT/EP2007/061351, filed Oct. 23, 2007, which claims priority under 35U.S.C. § 119 to German Patent Application No. DE 10 2006 050 647.2,filed Oct. 24, 2006, the entire disclosures of which are hereinexpressly incorporated by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a disc brake and, in particular, to a discbrake for a utility or commercial vehicle having a brake caliper, whichsurrounds a brake disc and which is fastened to a positionally fixedbrake carrier by two fastening elements so as to be axially movable inrelation to the brake disc. The fastening elements have, in each case,one guide bar which is fixedly connected to the brake carrier. For theaxial mobility of the brake caliper, one guide bar is guided in a plainbearing, which is embodied as a fixed bearing, and the other guide baris embodied as a floating bearing.

In such disc brakes, which are used predominantly in heavy utility orcommercial vehicles, the brake caliper, which is also referred to as asliding caliper, is connected to the vehicle-mounted brake carrier byway of fastening elements. Here, guide bars engage into the brakecarrier, which guide bars are guided at the other side in plain bearingsof the brake caliper, so as to enable an axial movement, in relation tothe brake disc, of the brake caliper with respect to the positionallyfixed brake carrier.

One of the plain bearings is designed as a fixed bearing with a smallamount of sliding play, while the other plain bearing functions as afloating bearing, as a result of which in particular productiontolerances are compensated.

Here, it has proven to be expedient to use a guide bush in the floatingbearing, which guide bush has a bearing sleeve composed of an elastomerand held in the brake caliper so as to be immovable. In addition to lowproduction costs, a guide bush of this type is characterized by acertain degree of robustness, and simple assembly. Furthermore,operational rattling noises are prevented by the elastomer bearingsleeve.

To protect the guide bar and the sliding surfaces which are formedtogether with the guide bush, it is known to cover the guide bar, on itsend side facing away from the brake disc, with a cap.

The guide bush itself, including the elastomer bearing sleeve, ishowever exposed, wherein in particular in the case of use in vehicleswhich are used on unsurfaced or very dirty roads, stone impacts andcontamination with dirt can result in damage to the guide bush, and theentry of dirty water into the guide region. This results in increasedbearing wear, which necessitates early replacement of the guide bush andpossibly of the guide bar. This is naturally associated withconsiderable cost expenditure, not least on account of the requiredinterruption in service of the vehicle.

The invention is therefore based on the object of further developing adisc brake such that the service life is increased, even under extremeoperating conditions, with little expenditure in terms of design andproduction.

This and other objects are achieved according to the invention byproviding a disc brake for a utility or commercial vehicle having abrake caliper, which surrounds a brake disc and which is fastened to apositionally fixed brake carrier by two fastening elements so as to beaxially movable in relation to the brake disc. The fastening elementshaving, in each case, one guide bar which is fixedly connected to thebrake carrier. For the axial mobility of the brake caliper, one guidebar is guided in a plain bearing which is embodied as a fixed bearing,and the other guide bar is guided in a plain bearing which is embodiedas a floating bearing. At least the floating bearing has (i) a guidebush, which engages around the guide bar and is connected to the brakecaliper so as to be immovable, (ii) an elastomer bearing sleeve, and(iii) a cap which covers the guide bar on its end side facing away fromthe brake disc. The cap is fastened, so as to cover the guide bush atthe end side, to the elastomer bearing sleeve at least in an axialpartial region at an outer side.

With little production expenditure, sealing is now obtained of thesliding region between the guide bush and the guide bar, whichconcomitantly encloses the elastomer guide bush. It is thus possible torefer to hermetic sealing of the plain bearing, by which operationalwear, caused for example by contamination and stone impacts, can beeliminated.

This naturally leads to a reduction in operating costs of the utilityvehicle which is used, since corresponding repair intervals arelengthened significantly.

Furthermore, disc brakes which are already in operation may beretrofitted with floating bearings according to the invention in theevent of repairs being carried out.

According to one advantageous refinement of the invention, provision ismade for the cap to be attached to the brake caliper, with theattachment region of the cap preferably being designed as an encircling,radially outwardly aligned collar, which can rest in a depression of thebrake caliper.

Provision is also made for the cap to be connected in a positivelylocking and/or frictionally locking manner to the guide bush.

Here, the cap may bear in a frictionally locking manner against theelastomer bearing sleeve. It is however also contemplated for the cap toalternatively or additionally be connected to a metal sleeve whichsurrounds the elastomer bearing sleeve. The metal sleeve is alsoencapsulated in regions by the elastomer bearing sleeve.

The connection of the cap to the metal sleeve, which is preferablycomposed of steel, takes place by an interference fit, while the contactof the elastomer bearing sleeve against the cap takes place byencircling, integrally formed lips, which bear under deformation againstthe inner wall of the cap.

In combination with the interference fit of the metal sleeve, reliablesealing of the floating bearing is thus obtained in a simple manner byway of the cap.

Further advantageous refinements of the invention are described herein.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of one ormore preferred embodiments when considered in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a disc brake in a schematic plan view;

FIG. 2 is a partial section view of the disc brake as per the label “A”in FIG. 1; and

FIG. 3 is an enlarged partial section view of a detail of the disc brakecorresponding to the label III in FIG. 2.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a disc brake, in particular for a utility orcommercial vehicle, which disc brake, in terms of its basic design, hasa brake caliper 2 which straddles a brake disc 3 fastened to an axle(not illustrated) of the vehicle.

The brake caliper 2 is arranged on a brake carrier 1 of the utilityvehicle so as to be axially movable in relation to the brake disc 3. Forthis purpose, two fastening elements are provided, which fasteningelements have, in each case, one guide bar 10 fixedly connected to thebrake carrier 1 (FIG. 2), by being fastened to the brake carrier 1 byway of a screw 11.

FIG. 2 illustrates an exemplary embodiment of a floating bearing 5. Thefloating bearing 5 includes a guide bush 9 engaging around the guide bar10 and being connected to the brake caliper 2 so as to be immovable. Anelastomer bearing sleeve 12 bears against the guide bar 10.

At an outer side, the elastomer bearing sleeve 12 is encased by a metalsleeve 13, which is connected thereto and which is encapsulated by theelastomer bearing sleeve 12 in regions, as can be seen particularlyclearly from FIG. 3.

On the side facing away from the brake disc 3, the end sides of theguide bar 10 and of the guide bush 9 are covered by a cap 7, which capis fastened in a positively locking and/or frictionally locking mannerto the guide bush 9.

On its open side facing toward the brake caliper 2, the cap 7 has anencircling, radially outwardly extending collar 14, which rests in adepression 15 of the brake caliper 2.

At an end facing away from the cap 7, the guide bush 9 bears against astop ring 16, which is supported in the brake caliper 2 and which servesto limit a maximum compression of the elastomer bearing sleeve 12 in theevent of externally acting forces.

The region, which faces toward the brake disc 3, between a holding bore,which holds the guide bush 9, and the guide bar 10, which projects withrespect to the guide bush 9, is sealed off by a bellows 8.

FIG. 3 illustrates an enlarged section of the connection of the cap 7 tothe guide bush 9. It can be seen that the metal sleeve 13 has aconstricted end region which is embedded by encapsulation into theelastomer bearing sleeve 12.

On the outer side facing toward the cap 7, the elastomer bearing sleeve12 is provided, in the region which covers the constriction, withencircling lips 17 which, before the cap 7 is placed on, project withrespect to the larger diameter of the metal sleeve 13.

To fasten the cap 7 to the guide bush 9, the cap 7 is pressed togetherwith the metal sleeve 13 in the region of the larger diameter, while thelips 17 bear under elastic deformation, corresponding to their restoringforces, against the inner wall of the cap 7. In this way, a connectionwhich is both secure and sealed is ensured between the cap 7 and theguide bush 9.

TABLE OF REFERENCE SYMBOLS

-   1 Brake carrier-   2 Brake caliper-   3 Brake disc-   4 Fixed bearing-   5 Floating bearing-   7 Cap-   8 Bellows-   9 Guide bush-   10 Guide bar-   11 Screw-   12 Elastomer bearing sleeve-   13 Metal sleeve-   14 Collar-   15 Depression-   16 Stop ring-   17 Lip

The foregoing disclosure has been set forth merely to illustrate theinvention and is not intended to be limiting. Since modifications of thedisclosed embodiments incorporating the spirit and substance of theinvention may occur to persons skilled in the art, the invention shouldbe construed to include everything within the scope of the appendedclaims and equivalents thereof.

1. A disc brake having a brake disc, the disc brake comprising: acaliper which, in use, straddles the brake disc; a positionally fixedcarrier; two fastening elements operatively configured to fasten thecaliper to the carrier so as to be axially moveable in relation to thebrake disc; each fastening element having a guide bar fixedly connectedto the carrier, one guide bar being guided in a plain bearing embodiedas a fixed bearing and the other guide bar being guided in a plainbearing embodied as a floating bearing; wherein at least the floatingbearing comprises a guide bush with an elastomer bearing sleeve, theguide bush engaging around the guide bar and being immovably connectedto the caliper; and wherein a cap covers an end side of the guide barfacing away from the brake disc, said cap being fastened to theelastomer bearing sleeve at least in an axial partial region at an outerside of the elastomer bearing sleeve in order to cover an end side ofthe guide bush.
 2. The disc brake as claimed in claim 1, wherein theelastomer bearing sleeve is encased at outer regions by a metal sleeve.3. The disc brake as claimed in claim 2, wherein the metal sleeve has,on a side facing toward the cap, a peripherally constricted regionembedded into the elastomer bearing sleeve.
 4. The disc brake as claimedin claim 1, wherein the cap is held in at least one of a positivelylocking and frictionally locking manner in a partial region of an outerwall of the elastomer bearing sleeve.
 5. The disc brake as claimed inclaim 4, wherein the cap is pressed onto the metal sleeve.
 6. The discbrake as claimed in claim 3, wherein a region of the elastomer bearingsleeve which covers the constriction of the metal sleeve is provided, onan outer side facing toward the cap, with at least one encircling lipwhich bears under elastic deformation against an inner wall of the cap.7. The disc brake as claimed in claim 1, wherein the cap bears againstthe caliper.
 8. The disc brake as claimed in claim 6, wherein the capbears against the caliper.
 9. The disc brake as claimed in claim 7,wherein the cap has a radially outwardly extending encircling collarwhich bears against the caliper.
 10. The disc brake as claimed in claim8, wherein the cap has a radially outwardly extending encircling collarwhich bears against the caliper.
 11. The disc brake as claimed in claim9, wherein the collar rests in a depression of the caliper.
 12. The discbrake as claimed in claim 1, wherein the guide bush bears, with an endside situated opposite the cap, against a stop ring held in the brakecaliper.